Classifications

• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09K—MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
  • C09K15/00—Anti-oxidant compositions; Compositions inhibiting chemical change
  • C09K15/04—Anti-oxidant compositions; Compositions inhibiting chemical change containing organic compounds
  • C09K15/30—Anti-oxidant compositions; Compositions inhibiting chemical change containing organic compounds containing heterocyclic ring with at least one nitrogen atom as ring member
• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
  • C07C7/00—Purification; Separation; Use of additives
  • C07C7/20—Use of additives, e.g. for stabilisation

Definitions

• the present invention relates to methods and compositions for inhibiting the polymerization of vinyl monomers, and more particularly relates, in one embodiment, to methods and compositions for inhibiting the polymerization of vinyl aromatic monomers.
• Still another object of the invention is to permit use of a composition to effectively inhibit the polymerization of styrene that has little or no environmental concerns.
• a composition for inhibiting polymerization of vinyl aromatic compounds that includes a dihydroxyarene, a hydrogen transfer agent, and a stable nitroxide.
• a dihydroxyarene or a substituted alkyl-dihydroxyarene, a hydrogen transfer agent, and a stable nitroxide is an effective treatment to control styrene monomer polymerization. This treatment protocol is most effective when formulated in an organic amine, although the composition may find effective use without the organic amine.
• suitable vinyl aromatic monomers that may be polymerization inhibited by the compositions and methods of this invention include, but are not necessarily limited to styrene, substituted styrene, divinylbenzene, vinyltoluene, vinyl naphthalene, polyvinylbenzenes, and isomers thereof.
• the aromatic monomer is styrene. It is anticipated that this invention could also inhibit the polymerization of non- aromatic vinyl compounds, e.g. acrylonitrile, vinyl chloride, acrylic acid and the like.
• Suitable substituted alkyl-dihydroxyarenes for the polymerization inhibiting composition of the invention may include, but are not necessarily limited to, substituted alkyl-dihydroxybenzenes having the formula:
• R 1 and R 2 are the same or different and are independently selected from the group consisting of hydrogen, straight, branched, and cyclic alkyl groups averaging from about 1 to about 6 carbon atoms, preferably from about 1 to about 4 carbon atoms, and where x averages from about 0 to about 9, and preferably in one embodiment from about 1 to about 9. In one preferred embodiment, both R 1 and R 2 are not simultaneously hydrogen.
• Examples of specific substituted alkyl-dihydroxyarenes that would be suitable in the composition of this invention include, but are not necessarily limited to, hydroquinone; tert-butylhydroquinone; 2,5-di-tert-butylhydroquinone; tert-butylcatechol; hydroquinone; 3,5-di-tert-butylcatechol; catechol; 3,33 ⁇ 3'-tetramefhyl-l ,r-spiro-bj ' s- indane-5,5',6,6'-teterol; and mixtures thereof.
• Hydrogen Transfer Agent suitable for use in the polymerization inhibiting composition of this invention include, but are not necessarily limited to, naphthalene; anthracene; decalin; hydroquinoline; 1,23,4-tetrahydronaphthalene (TETRALIN ® ; DuPont); 9,10-dihydroanthracene; fluorene; squalane; squalene; tetramethylhydroquinoline; and mixtures thereof.
• TETRALIN ® 1,23,4-tetrahydronaphthalene
• the stable nitroxide of the composition useful for inhibiting polymerization of vinyl aromatic compounds may include, but are not necessarily limited to those having the formula:
• R 3 , R 4 , R 5 , and R 6 are the same or different and are independently selected from the group consisting of straight, branched, or cyclic alkyl groups of from 1 to about 9 carbon atoms, preferably from about 1 to 3 carbon atoms; where Z is selected from the group consisting of hydrogen, oxygen, alkyl groups, alkoxy groups, hydroxyl, aryl groups, alkaryl groups, heterocyclic alkyl groups; and where when Z contains carbon atoms, may contain an average of from about 1 to 9 carbon atoms, preferably from about 1 to 3 carbon atoms.
• R 3 and R 4 may be joined together to form a cyclic moiety which may be alkylene or aralkylene. The same is true for the R 5 and R 6 pair.
• stable nitroxides examples include, but are not necessarily limited to, 2,2,6,6-tetramethyl-l- piperidinyloxyl (TEMPO); 4-OXO TEMPO; l-oxyl-2,2,6,6-tetramethylpiperidine; 1- oxyl-2,2,6,6-tetramethylpiperidin-4-one; l-oxyl-2,2,6,6-tetramethylpiperidin-4-yl-2- acetate; l-oxyl-2,2,6,6-tetramethyl-l-piperidin-4-yl-2-ethylhexanoate and mixtures thereof.
• the stable nitroxides may include, but are not necessarily limited to those having the formula:
• R 9 R 10 R n )C [(R 9 R 10 R n )C] 2 N-O * where R°, R 10 , and R 1 ' are independently selected from the group consisting of hydrogen, straight, branched or cyclic alkyl, aryl, aralkyl, and alkaryl moieties; where only one of R 9 , R 10 , and R 1 ' on each C can be hydrogen at a time; where one or more of R 9 , R 10 , and R 1 ' on one C may be joined to a R 9 , R 10 , and R 1 ' on the other C to form a cyclic moiety selected from the group consisting of alkylene, and aralkylene moieties; where any two of the R 9 , R 10 , and R 1 ' on any one C may be joined together to form a cycloalkyl; where any of the above definitions of R 9 , R 10 , and R 1 ' may contain one or more heteroatoms selected from the
• Organic amines suitable in the methods and compositions of this invention may include, but are not necessarily limited to, organic amines of the formula:
• R 7 -NH-R 8 where R 7 and R 8 are the same or different and are independently selected from the group consisting of hydrogen; straight, branched, and cyclic alkyl groups; alkoxy groups; hydroxyalkyl groups; and aminoalkyl groups; averaging of from about 1 to about 20 carbon atoms, preferably from about 6 to about 9 carbon atoms, where both R 7 and R 8 are not simultaneously hydrogen.
• Examples of specific organic amines that would be suitable in the composition of this invention include, but are not necessarily limited to, butylamine; hexylamine; n- octylamine; dodecylamine; cyclohexylamine; N,N-dihexylamine; ethanolamine; N-(2- aminoethyl)ethanol; ethylenediamine; 2-aminopropanol; and mixtures thereof.
• the composition of this invention may have from about 1 to about 10,000 ppm of the alkyl-dihydroxyarene; from about 1 to about 10,000 ppm of the hydrogen transfer agent; and from about 1 to about 10,000 ppm of the stable nitroxide, based on the total amount of vinyl aromatic compound being treated.
• the proportions range from about 34 to about 200 ppm of the alkyl- dihydroxyarene; from about 34 to about 118 ppm of the hydrogen transfer agent; and from about 34 to about 145 ppm of the stable nitroxide, based on the total amount of vinyl aromatic compound being treated.
• the composition of this invention may have from about 1 to about 10,000 ppm of the alkyl-dihydroxyarene; from about 1 to about 10,000 ppm of the hydrogen transfer agent; from 1 to about 10,000 ppm of the stable nitroxide and from about 1 to about 10,000 ppm of the organic amine, based on the total amount of vinyl aromatic compound being treated.
• the proportions range from about 34 to about 200 ppm of the alkyl-dihydroxyarene; from about 34 to about 118 ppm of the hydrogen transfer agent; from about 34 to about 145 ppm of the stable nitroxide and from about 5 to about 300 ppm of the organic amine, based on the total amount of vinyl aromatic compound being treated.
• the components of the composition may be simply mixed together. They may be mixed together in a single composition prior to addition to the vinyl aromatic compound, although they may also be added to the vinyl compound separately.
• Inhibited styrene monomer purchased from Aldrich Chemicals was distilled under vacuum (45°C, 29 mm Hg) to remove the conventional storage inhibitor 4-tert-butyl- pyrocatechol. The distilled styrene was checked for polymer content by sampling a portion and mixing in cold methanol. The distillation of the styrene monomer is considered successful if the two liquids mix completely with no presence of haze or cloudy appearance. One hundred mis of distilled styrene was transferred into a 250 ml, three-necked, round bottom reaction flask. The desired amount of inhibitors) were added to the distilled styrene monomer.
• the reaction flask was also equipped with a condenser, a thermocouple (type J), thermometer (Celsius), and a gas sparge tube.
• the reaction apparatus was placed in an oil bath. The temperature of the oil bath could be raised by the use of an external heating device.
• the styrene monomer was purged with nitrogen for 20 minutes to insure that the effect of oxygen on styrene monomer and/or inhibitors would be insignificant during the test run. While continuing the nitrogen purge, the temperature of the oil bath and subsequently, the styrene/inhibitor(s) composition was raised until a styrene monomer/inhibitor(s) composition temperature of 118°C ⁇ 2°C was obtained.
• the styrene monomer/inhibitor(s) composition was maintained under these conditions for 90 minutes.
• the reaction flask apparatus was removed from the hot oil bath and the styrene monomer/inhibitor(s) composition was allowed to cool to ambient under continuing nitrogen purge.
• the styrene monomer/inhibitor(s) composition was transferred from the reaction flask into a 1000 ml beaker containing 200 ml of cold methanol.
• the styrene/methanol mixture was mixed until the polymer, if any, agglomerates. Eight hundred ml of n-heptane was added to the styrene methanol composition.
• the polystyrene if any, was allowed to settle out of solution until the liquid phase of the composition was clear.
• the styrene/methanol/n- heptane/polymer mixture was filtered through a 1.0 ⁇ m glass fiber filter. Any remaining polymer was washed from the beaker with n-heptane through the glass fiber filter paper.
• the filter paper was placed into an oven with ventilation capable of maintaining a temperature of 150°C ⁇ 2°C for 16 hours.
• the dried polymer was cooled in a desiccator, and the weight of the polymer was obtained by taking the difference of the weight of filter paper/polymer minus the initial weight of filter paper. Results were reported as percent polymer formed by weight of polymer formed in mgs divided by the weight of the original styrene monomer used in mg multiplied by 100.
• Uninhibited styrene monomer prepared by the above procedure stored at -25°F (- 13°C) was used to evaluate the additives of the instant invention, as described below. As noted, a 90 minute nitrogen reflux test method was used to generate the data. Table I summaries the results from the initial testing.
• test apparatus is equipped with a septum and a 5 ml sample is extracted with a syringe at designated time intervals.
• Example 32 The data below summarizes the amount of polymer formed during the duration of the test when using the combination of inhibitors: 52 ppm TETRALIN, 87 ppm 2,5-di- tert-butyl HQ, and 65 ppm 4-OH TEMPO formulated in n-octylamine. Samples were extracted as in Example 31.
• Table VII shows that even when the di-hydroxyarene compound is not formulated in an organic amine the combinations of stable free radical, hydrogen transfer agent and di-hydroxyarene materials are still quite effective.

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• 1999
  • 1999-09-08 AT AT99944100T patent/ATE230714T1/de not_active IP Right Cessation
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